Internal combustion engines (IC engines) use either a 2 strokes or a 4 strokes thermodynamic cycle. The internal combustion engine basically includes a cylinder 2 containing a piston 4 affecting a reciprocal movement which is converted into a rotative movement by means of a connecting rod 6 and a crankshaft 8.
In a 4 strokes internal combustion engine, the piston completes four separate strokes which constitute a single thermodynamic cycle. A stroke refers to the full travel of the piston along the cylinder, in either direction.
FIG. 1 shows the four separate strokes of a conventional IC engine:
Intake stroke: in this stroke, the piston 4 begins at top dead center (TDC). The piston 4 descends from the top of the cylinder 2 to the bottom of the cylinder, increasing the volume of the cylinder 2. A mixture of fuel and air is forced by atmospheric (or greater) pressure into the cylinder through the intake valve 3.
Compression stroke: with both intake 3 and exhaust valves 5 closed, the piston 4 returns to the top of the cylinder 2 compressing the air or fuel-air mixture into the cylinder head.
Combustion stroke: this is the start of the second revolution of the cycle. While the piston 4 is close to top dead center (TDC), the compressed air-fuel mixture in a gasoline engine is ignited, by a spark plug 7. The resulting pressure from the combustion of the compressed fuel-air mixture forces the piston 4 back down toward bottom dead center (BDC).
Exhaust stroke: during the exhaust stroke, the piston 4 returns to the top dead center (TDC) while the exhaust valve 5 is open. This action expels the spent fuel-air mixture through the exhaust valve(s).
Two strokes IC engines are also very common, but they are less efficient and emit more noxious chemicals than a 4 strokes engine.
Many improvements have been made to IC engines over the years to improve the engine performance. The improvements basically try to prolong the cycles of the conventional strokes by using extendable connecting rods, using absorbing springs, using support pins for the piston, using long or short piston runs, or oval crankshafts. Unfortunately, the known prior art improvements are generally characterized by relatively complex, multiple linkage systems which would increase power loss due to added friction and inertia of the multitude of moving parts.
There is a need for a system that improves the engine performance without using complex and multiple linkage systems.